KR20200144572A - Method for producing chlorosilane - Google Patents

Abstract

In a fluidized bed reactor, the general formula H _n SiCl _4-n and/or H _m Cl by reaction of a contact material containing silicon and a reaction gas containing hydrogen chloride as a granulation mixture consisting of a coarse particle fraction and a fine particle fraction _6-m Si ₂ (where n = 1~4 and m = 0~4) a method for producing chlorosilanes, the average particle size of the fine grain fraction d _50, a _fine average particle size of the coarse grain fraction d _{50, It} relates to a manufacturing method that is smaller than the _coarse .

Description

Method for producing chlorosilane

The present invention, in a fluidized bed reactor, by reacting a contact material containing silicon and a reaction gas containing hydrogen chloride as a granulation mixture consisting of a coarse particle fraction and a fine particle fraction, the general formula H _n SiCl _4-n and/or H _m Cl _It relates to a method of preparing a chlorosilane of _6-m Si ₂ (where n = 1 to 4 and m = 0 to 4).

The production of polycrystalline silicon as a starting material for chip or solar cell production is typically carried out by decomposition of its volatile halogen compounds, in particular chlorosilanes such as trichlorosilane (TCS, HSiCl ₃ ). In order to meet the requirements for the manufacture of chips or solar cells, the purity of polycrystalline silicon must be at least 99.9%. When the purity exceeds 99.9%, the term ultra-high purity silicon is used.

The preparation of chlorosilanes, in particular TCS, can be carried out by three processes essentially based on the following reactions (see WO 2010/028878 A1 and WO 2016/198264 A1):

(1) SiCl ₄ + H ₂ -> SiHCl ₃ + HCl + by-product

(2) Si + 3SiCl ₄ + 2H ₂ -> 4SiHCl ₃ + by-product

(3) Si + 3HCl -> SiHCl ₃ + H ₂ + by-product

By-products that can be produced include additional halosilanes, such as monochlorosilane (H ₃ SiCl), dichlorosilane (H ₂ SiCl ₂ ), silicon tetrachloride (STC, SiCl ₄ ) and di- and oligosilanes. Impurities such as hydrocarbons, organic chlorosilanes and metal chlorides can also be constituents of by-products. Thus, distillation generally follows in order to produce high purity TCS.

The high temperature conversion according to reaction (1) is an endothermic process, and is generally carried out under high pressure at a temperature of 600°C to 900°C.

The low temperature conversion (LTC) according to reaction (2) is carried out in the presence of a catalyst (eg, a copper containing catalyst). LTC can be carried out in a fluidized bed reactor in the presence of Si _mg at a temperature of 400°C to 700°C.

Hydrogen chloride addition reaction (HC) according to reaction (3) makes it possible to produce chlorosilane from metal grade silicon (Si _mg , "metallurgical grade" silicon) and hydrogen chloride (HCl) in a fluidized bed reactor. It is an exothermic reaction. This generally yields TCS and STC as the main products. The process for HC is disclosed, for example, in US 4092446 A.

The most important parameters affecting the performance of HC are in principle TCS selectivity, HCl conversion, silicon conversion and by-product formation. HC is for example as described in Sirtl et al. (Z. anorg. allg. Chem. 1964, 332, 113-216) or Hunt et al. (J. Electrochem. Soc. 1972, 119, 1741-1745). It is based on the thermal equilibrium reaction of chlorosilane. HC in thermal equilibrium in principle forms not only chlorine-containing monosilanes (H _n Cl _4-n Si, where n = 1-4), but also high boiling di-, oligo- and/or polychlorosilanes.

The term “high boiling point compound” or “high boiling point substance” refers to a compound consisting of silicon, chlorine and optionally hydrogen, oxygen and/or carbon and having a boiling point higher than STC (57° C. at 1,013 hPa). In general, these include disilane H _m Cl _6-m Si ₂ (m = 0-4) and higher oligo- or poly(chloro)silanes.

WO 2007/101789 A1 and the literature cited therein refer to a process for converting high-boiling substances into chlorine-containing monosilanes, preferably TCS, and returning them to a value chain. However, this process entails additional technical complexity. Therefore, a process that minimizes or prevents the formation of unwanted high-boiling point substances immediately in the manufacturing process is particularly desirable.

In addition to the formation of undesirably high STC and high boiling point materials, the process costs increase in principle due to unconverted HCl and unconverted silicon.

In the production of chlorosilanes in a fluidized bed reactor, it is known to specifically remove the fine particle fraction of the silicon particles used. For example, Lobusevich et al. refer to working granulation on silicon of 70-500 μm, where 70 μm is the minimum particle size, 500 μm is the maximum particle size (particle size limit or range limit), and these values are equivalent diameters (Khimiya Kremniiorganich. Soed. 1988, 27-35). Working granulation describes the granulation introduced into a fluid bed reactor. DE 3938897 A1 refers to a preferred working granulation for silicon of 50-800 μm, and RU 2008 128 297 A refers to a preferred working granulation of 90-450 μm. Lobusevich et al. report that when choosing the contact material particle size for the synthesis of methyl chlorosilane, ethyl chlorosilane and TCS, the interaction between solids and gases should be considered to achieve maximum stability and efficiency of the process. Thus, in the synthesis of TCS (at 400° C.), the working granulation of 2-3 mm reduced the reaction rate by about 25% to 30% compared to the working granulation of 70-500 μm. Upon addition of the copper-containing catalyst, the reaction with the silicon particles of the working fraction 2-3 mm already takes place at 250°C. The reaction rate is consistent with that of the variant without using a catalyst at 400°C. In both cases-both catalyst and non-catalyst variants-increasing the silicon particle size increases the TCS selectivity and reduces the formation of polychlorosilanes (high boiling point substances).

Increasing the particle size usually entails higher energy costs, as higher reaction temperatures are required to accelerate the reaction and faster gas velocities are required to create a fluidized bed. Lobusevich et al. argued that using a smaller proportion of silicon particles in a polydisperse particle mixture improves the activity of silicon due to an increase in the surface area, and using a small proportion of silicon particles increases the release of silicon particles from the reactor and reduces particle aggregation. Report that difficulties are involved because they can occur. Therefore, according to Lobusevich et al., despite the high energy cost, it is advantageous to reduce the width of the particle size distribution of the used silicon particles and increase the average particle size.

The present invention aims to provide a particularly economical method for the production of chlorosilanes.

This purpose is, in a fluidized bed reactor, a granulation mixture consisting of a coarse particle fraction and a fine particle fraction, by reaction of a contact material containing silicon and a reaction gas containing hydrogen chloride to obtain the general formula H _n SiCl _4-n and/or H _m Cl _6-m Si ₂ (where n = 1~4 and m = 0~4) a method for producing chlorosilanes, the average particle size of the fine grain fraction d _50, a _fine average particle size of the coarse grain fraction d _{50, It} is achieved by a manufacturing method that is smaller than the _coarse .

The term "granulation" is to be understood as meaning in particular a mixture of silicon particles which can be produced by grinding chunk silicon, for example by means of a crushing and milling plant. The chunk silicon may have an average particle size of> 10 mm, preferably> 20 mm, particularly preferably> 50 mm. Granulation can essentially be classified into fractions by sieving and/or shifting.

Granulation can be prepared by/from:

-Crushing and milling of chunk silicon; Subsequent sieving and/or shifting (classification) as appropriate;

-Waste, especially in the form of dust generated from the processing (crushing, milling, sawing) of various types of silicon (wafer, polycrystalline/multicrystalline/single crystal silicon, Si _mg ) and classified as the case may be, over and/or Underlying waste, fractions outside the target granulation are included;

-The process of producing granulated Si _mg or polycrystalline silicon.

Mixtures of various granulations can be described as granulation mixtures, and the granulations constituting the granulation mixture can be described as granulation fractions. The granulated fraction can be classified into a coarse particle fraction and a fine particle fraction with respect to each other. In the granulation mixture, it is in principle possible to classify more than one granulation fraction into coarse particle fractions and/or fine particle fractions.

It is preferable that the difference ( d _{50, coarse} - d _{50, fine} ) is> 1 μm, preferably> 10 μm, particularly preferably> 50 μm, particularly> 100 μm. Difference ( d _{50, coarse} -d _{50, fine} ) is preferably in the range of 10 to 700 μm, preferably 50 to 500 μm, particularly preferably 75 to 450 μm, and particularly 100 to 350 μm.

The average particle size d ₅₀ of the coarse particle fraction _{, the coarse} may be 100 to 800 µm, preferably 125 to 600 µm, particularly preferably 150 to 500 µm, in particular 175 to 400 µm.

The average particle size d ₅₀ of the fine particle fraction _{, fine} may be 100 to 500 µm, preferably 5 to 400 µm, particularly preferably 10 to 300 µm, in particular 15 to 175 µm.

Compared to the generally used coarse particle fraction, the use of the fine particle fraction according to the present invention results in an average particle size d ₅₀ of the granulation mixture _{, and the mixture} is transferred to a smaller particle size. The particle size distribution widens together.

Surprisingly, it has been found that such granulation mixtures with a wider particle size distribution achieve at least the same TCS selectivity while producing less high boiling point by-products than in the case of known processes. This overcomes the preconceived notion of Lobusevich et al. that the formation of high boiling point substances decreases and TCS selectivity increases as the average particle size increases only in the case of granulation mixtures having a narrow size distribution. Moreover, it has been found that the process according to the invention can achieve significantly higher HCl conversions. Surprisingly, no negative effects expected according to the current knowledge of average particle size reduction, such as an increase in the release of relatively small silicon particles from the reactor and the occurrence of agglomeration effect, were surprisingly observed. Indeed, improved fluidization behavior of the contact material was observed in the process according to the invention. In addition, the presence of a fine particle fraction leads to the further advantage of the improved flow behavior of the granulating mixture, thus simplifying its transport and feeding in particular to the reactor.

The d ₅₀ value specifies the average particle size (see ISO 13320). A value of d ₅₀ means that 50% of the particles are less than the specified value. Additional important parameters for characterization of the particle size distribution are, for example, the d ₁₀ value as a measure for smaller particles in the fraction or granulation mixture in question and the d ₉₀ value as a measure for larger particles. The values d ₁₀ and d ₉₀ can also be used to describe the width of the particle size distribution:

Width = d ₉₀ - d ₁₀

To determine the relative width of the particle size distribution, the so-called span of the particle size distribution can be used:

Span = ( d ₉₀ - d ₁₀ )/ d ₅₀

Span is, in principle, used when comparing particle size distributions with very different mean particle sizes.

The determination of the particle size distribution can be carried out according to ISO 13320 (laser diffraction) and/or ISO 13322 (image analysis). The calculation of the average particle size/diameter from the particle size distribution can be carried out according to DIN ISO 9276-2.

It is preferred when the granulation mixture has a volume weighted distribution density function of p-mode of p = 1 to 10, preferably p = 1 to 6, particularly preferably p = 1 to 3, in particular p = 1 or 2 Do. For example, the 2-mode distribution density function has two maximum values.

By using a granulation mixture with a multimodal (e.g. p = 5 to 10) distribution density function, shifting effects (e.g. separation of individual particle fractions in a fluidized bed such as a two-part fluidized bed) can be avoided. have. This effect occurs especially when the maximum value of the distribution density function of the granulation mixture is far apart.

Further if the coarse particle fraction and/or the fine particle fraction has a volume weighted distribution density function of p-mode, p = 1 to 5, preferably p = 1 to 3, particularly preferably p = 1 or 2 It may be desirable.

As already mentioned, fine particle fractions of silicon with different particle size distributions can be produced as wastes in various processes, and can be combined to produce fine particle fractions of multiple modes (p ≥ 2). The purchase of these fine particle fractions is generally inexpensive and improves the economics of the process. The use of these fine particle fractions allows the use of a coarser standard working fraction, thus ensuring capacity in the milling plant.

d _{50, fine} and d _{50, coarse} grain size ratio (GSR) d _{50, fine} / d _{50, coarse} 0.01 to 0.99, preferably 0.02 to 0.9, particularly preferably 0.03 to 0.7, particularly 0.04 to It is preferable when it is present at 0.6. GSR can also be referred to as the particle size ratio.

The fine particle fraction and the coarse particle fraction are preferably 0.01 to 99, preferably 0.05 to 20, particularly preferably 0.09 to 10, particularly at a mass ratio (MR) m (fine) / m (coarse) of 0.1 to 4 exist.

It is preferred that the granulation mixture has a span of 0.01 to 2000, preferably 0.1 to 500, particularly preferably 1 to 100, especially 1.5 to 10 particle size distribution ( d ₉₀ - d ₁₀ )/ d ₅₀ .

The contact material is in particular a granulation mixture. It is preferred if the contact material does not contain additional components. This is preferably a silicon containing 5% by weight or less, particularly preferably 2% by weight or less, especially 1% by weight or less, of other elements as impurities. Preferably this corresponds to _mg of Si, typically having a purity of 98% to 99.9%. A typical composition is, for example, a composition comprising 98% silicon, the remaining 2% is usually usually the following elements: Fe, Ca, Al, Ti, Cu, Mn, Cr, V, Ni, Mg, B, C, It consists of P and O. The following elements may also be present: Co, W, Mo, As, Sb, Bi, S, Se, Te, Zr, Ge, Sn, Pb, Zn, Cd, Sr, Ba, Y and Cl. However, it is also possible to use silicon with a low purity of 75% to 98%. However, it is preferred if the silicon ratio is more than 75%, preferably more than 85%, particularly preferably more than 85%.

Some of the elements present as impurities in silicon have catalytic activity. Therefore, addition of a catalyst is in principle unnecessary. However, the presence of additional catalysts can have a positive effect on the process, especially in terms of selectivity.

In one embodiment, the silicon used is a mixture of Si _mg and ultra-high purity silicon (purity> 99.9%). That is, a granulation mixture containing Si _mg and ultra-high purity silicon is applicable. Here, it is preferable that the proportion of Si _mg is 50% by weight or more, preferably 70% by weight or more, particularly preferably 90% by weight or more, based on the total weight of the granulation mixture. Ultra-high purity silicon is in particular a constituent of the fine particle fraction. It is also possible for the fine particle fraction to contain only ultra-high purity silicon.

In a further embodiment, the silicon used is Si _mg and ultrapure silicon, wherein the proportion of Si _mg is less than 50% by weight, based on the total weight of the granulation mixture. It is preferred here when the granulation mixture/contact material further comprises a catalyst. The ultra-high purity silicon and/or catalyst is preferably a constituent of the fine particle fraction. It is preferred when the fine particle fraction consists of ultra-high purity silicon.

In another embodiment, the silicon used is only ultra-high purity silicon, and the contact material/granulation mixture includes a catalyst. It is preferable here that the catalyst is a constituent of the fine particle fraction.

The fine particle fraction may be, for example, a by-product produced in the deposition of polycrystalline silicon according to the Siemens method or the granulation process. It may also be a by-product produced from the mechanical treatment of poly(poly) crystal/poly(multi) crystal or single crystal silicon (purity> 99.9%). The ultra-high purity silicon dust produced as a by-product can be applied to a milling process to obtain a desired particle size and/or to a classification process to obtain granules having a desired particle size limit.

Ultrahigh purity silicon can in principle be converted by HC only in the presence of a small amount of one of the elements cobalt, molybdenum and tungsten (generally already present as an impurity in ultrahigh purity silicon). The general conversion with Si _mg containing a larger amount of catalytically active element as an impurity is not essential. However, the chlorosilane selectivity can be increased by adding a catalyst. This may be the case in this process, especially when the proportion of ultra-high purity silicon in the granulation mixture is higher than that of Si _mg and/or when the granulation mixture contains only ultra-high purity silicon.

Catalysts are Fe, Cr, Ni, Co, Mn, W, Mo, V, P, As, Sb, Bi, O, S, Se, Te, Ti, Zr, C, Ge, Sn, Pb, Cu, Zn, It may be one or more elements selected from the group including Cd, Mg, Ca, Sr, Ba, B, Al, Y, and Cl. The catalyst is preferably selected from the group comprising Fe, Al, Ca, Ni, Mn, Cu, Zn, Sn, C, V, Ti, Cr, B, P, O, Cl and mixtures thereof. As mentioned above, these catalytically active elements are already present in silicon in certain proportions as impurities, for example in the form of oxides or metals, as silicides or other metallurgical or as oxides or chlorides. The ratio depends on the purity of the silicon used.

The catalyst can be added to the contact material, for example in the form of metals, alloys and/or salts. Chlorides and/or oxides of catalytically active elements may in particular be of interest. Preferred compounds are CuCl, CuCl ₂ , CuO or mixtures thereof. The contact material may additionally contain a cocatalyst, for example Zn and/or zinc chloride.

The elemental composition of the silicon and contact material used can be determined, for example, by x-ray fluorescence analysis.

It is preferred that the fine particle fraction and the coarse particle fraction are fed to the fluidized bed reactor as a granulation mixture prepared in advance. Any additional components of the contact material may likewise be present therein. The more fine particle fraction according to the invention results in an improved flow, conveying the behavior of the pre-prepared granulation mixture.

The fine particle fraction and the coarse particle fraction may be fed separately to the fluidized bed reactor, especially via separate feeds and vessels. Thereby mixing is in principle carried out during (in situ) formation of the fluidized bed. The additional constituents of the contact material can likewise be supplied separately or as one constituent of the two particle fractions.

It is preferred to carry out the process at a temperature of 280°C to 400°C, preferably 320°C to 380°C, particularly preferably 340°C to 360°C. The pressure in the fluidized bed reactor is preferably 0.01 to 0.6 MPa, preferably 0.03 to 0.35 MPa, particularly preferably 0.05 to 0.3 MPa.

The reaction gas preferably contains at least 50% by volume, preferably at least 70% by volume, particularly preferably at least 90% by volume HCl. In addition to HCl, the reaction gases are H ₂ , HnSiCl _4-n (n = 0 to 4), H _m Cl _6-m Si ₂ (m = 0 to 6), H _q Cl _6-q Si ₂ O (q = 0 To 4), CH ₄ , C ₂ H ₆ , CO, CO ₂ , O ₂ , N _{2 It} may further include one or more components selected from the group containing. These components can be derived from HCl recovered in the integrated system. HCl and silicon are preferably 5:1 to 3:1, preferably 4:1 to 3:1, particularly preferably 3.6:1 to 3:1, in particular 3.4:1 to 3.1:1 HCl/Si It exists in a molar ratio. HCl and the contact material/granulation mixture or particle fractions thereof are added continuously throughout the reaction, in particular so that the ratios mentioned above are established.

It is preferable that the ratio of the fluidized bed height to the reactor diameter is 10:1 to 1:1, preferably 8:1 to 2:1, particularly preferably 6:1 to 3:1. The fluidized bed height is the thickness or range of the fluidized bed.

The chlorosilane prepared by the method according to the present invention is preferably at least one chlorosilane selected from the group comprising monochlorosilane, dichlorosilane, TCS, Si ₂ Cl ₆ and HSi ₂ Cl ₅ . It is particularly preferred with respect to TCS.

The method according to the invention is preferably integrated into an integrated system for producing polycrystalline silicon. The integrated system in particular comprises the following processes:

-Production of TCS according to the described process.

-Provides semiconductor quality TCS by refining the produced TCS.

-Preferably, polycrystalline silicon is deposited by the Siemens process or as granules.

-Further processing of the obtained polycrystalline silicon.

-Ultra-high purity silicon dust generated in the production/additional treatment of polycrystalline silicon is recycled by the reaction according to the above process.

1 shows by way of example a fluidized bed reactor 1 for carrying out the process according to the invention. The reactant gas 2 is preferably injected into the contacting material from below and optionally from the side (e.g., tangentially or orthogonal to the gas stream from below) to fluidize the particles of the contacting material and thereby fluidize the fluidized bed ( 3) to form. The reaction is generally initiated by heating the fluidized bed 3 by means of a heating device (not shown) disposed outside the reactor. Heating is generally not required during continuous operation. Some of the particles are carried by the gas flow from the fluidized bed 3 to the free space 4 above the fluidized bed 3. The free space 4 is characterized by a very low solid density, which density decreases in the direction of the reactor exit.

Example

The examples were carried out in a fluidized bed reactor, for example as described in US4092446.

All examples used the same silicon type fine particle fraction and/or coarse particle fraction in terms of purity, quality and content of secondary elements/impurities. Particle fraction was produced by crushing of chunk Si _mg and subsequent milling. Subsequently, in some cases, final classification by sieve was performed. Measurement of the particle size distribution was carried out according to ISO 13320 and/or ISO 13322. All examples used the following process.

General procedure:

The initially charged layer of contact material was first applied to a cross flow of nitrogen (carrier gas) until a fluidized bed was formed. The ratio of the fluidized bed height to the reactor diameter was set to a value of about 5. The reactor diameter was about 1 m. The fluidized bed was brought to a temperature of about 320° C. with an external heating device. This temperature was kept almost constant throughout the entire experiment using cooling means. HCl was added and additional contacting material was charged so that the height of the fluidized bed was kept substantially constant for the total duration of the experiment and a constant molar ratio of the reactants (HCl:Si) of 3:1. The reactor was operated at a positive pressure of 0.1 MPa throughout the entire experimental period. Each liquid and gas sample was taken 48 and 49 hours after run time. The condensable proportion of the product gas stream (chlorosilane gas stream) was condensed in a cold trap at -40°C and analyzed by gas chromatography (GC), to determine the TCS selectivity and the proportion [% by weight] of the high boiling point material. Was used. Detection was made through a thermal conductivity detector. The non-condensing percentage of the product gas stream was analyzed for unconverted HCl [vol.%] using an infrared spectrometer. Each average value was obtained from the values obtained after 48 and 49 hours. The reactor was completely emptied and filled with fresh contact material after each run.

Comparative Example 1:

The contact material consisted of only a coarse particle fraction ( d ₅₀ = 683 μm, range limit: 600 to 700 μm) of Si _mg with a narrow particle size distribution (span: 0.09, where d ₁₀ = 631 μm and d ₉₀ = 694 μm) .

The following values were obtained:

-Ratio of unconverted HCl: 32 vol%

-TCS selectivity: 91%

-Ratio of high boiling point substances: 0.7% by weight

Comparative Example 2:

The contact material consists only of a coarse particle fraction of Si _mg ( d ₅₀ = 211 μm, range limit: 90-450 μm) with a wider particle size distribution (span: 1.62, where d ₁₀ = 95 μm and d ₉₀ = 437 μm). lost.

The following values were obtained.

-The proportion of unconverted HCl: 16 vol%

-TCS selectivity: 88%

-Ratio of high boiling point substances: 0.7% by weight

Comparative Example 3:

The contact material consisted of only a fine particle fraction of Si _mg ( d ₅₀ = 48.6 μm, range limit: <90 μm). The span of the particle size distribution was 1.35 ( d ₁₀ = 18.9 µm and d ₉₀ = 84.3 µm).

The following values were obtained.

-Ratio of unconverted HCl: 0.7 vol%

-TCS selectivity: 74%

-Ratio of high boiling point substances: 0.6% by weight

Example 1:

The contact material was a fine particle fraction and a coarse particle fraction (GSR: 0.12, where d _{50, fine} = 50.4 μm and d _{50, coarse} = 420 μm, MR: 0.43, span: 5.22, where d _{10, GM} = 46.0 μm and d _{90, GM} = 840 μm) of Si _mg containing granulation mixture (GM). The d ₅₀ of GM was 152 μm. The pre-prepared GM was initially charged to the reactor as a bed and fed continuously during the process.

The following values were obtained.

-Ratio of unconverted HCl: 4 vol%

-TCS selectivity: 89%

-Ratio of high boiling point substances: 0.2% by weight

Example 2:

The contact material was a fine particle fraction and a coarse particle fraction (GSR: 0.12, where d _{50, fine} = 50.4 µm and d _{50, coarse} = 420 µm, MR: 1.0, span: 7.51, where d1 _{0, GM} = 34.0 µm and d _{90, GM} = 680 [mu]m) of Si _mg granulation mixture (GM). The d ₅₀ of GM was 86 μm. The pre-prepared GM was initially charged to the reactor as a bed and fed continuously during the process.

The following values were obtained.

-Ratio of unconverted HCl: 2 vol%

-TCS selectivity: 88%

-Ratio of high boiling point substances: 0.1% by weight

The above results show that the method according to the invention avoids the formation of high boiling point materials. The TCS selectivity is high, similar to the comparative example.

Claims (15)

In a fluidized bed reactor, the general formula H _n SiCl _4-n and/or H _m Cl _6-m Si by reaction of a contact material containing silicon and a reaction gas containing hydrogen chloride as a granulation mixture consisting of a coarse particle fraction and a fine particle fraction ₂ (where n = 1~4 and m = 0~4) a method for producing chlorosilanes, the average particle size of the fine grain fraction d _50, a _fine average particle size of the coarse grain fraction d _50, is smaller than _{the coarse} Phosphorus manufacturing method. The volume weighting of the p-mode according to claim 1, wherein the granulation mixture is p = 1 to 10, preferably p = 1 to 6, particularly preferably p = 1 to 3, in particular p = 1 or 2 A manufacturing method, characterized in that it has a distribution density function. The particle size ratio d ₅₀ according to claim 1 or 2, wherein d _{50, fine silver} and d _{50, coarse size} , 0.01 to 0.99, preferably 0.02 to 0.9, particularly preferably 0.03 to 0.7, particularly 0.04 to 0.6 _{, Fine} / d _50, Manufacturing method, characterized in that present as _coarse . The mass ratio m ( fine particles) according to any one of claims 1 to 3, wherein the fine particle fraction and the coarse particle fraction are from 0.01 to 99, preferably from 0.05 to 20, particularly preferably from 0.09 to 10, in particular from 0.1 to 4 )/ m ( coarse ). The method according to any one of claims 1 to 4, wherein the granulation mixture is from 0.01 to 2000, preferably from 0.1 to 500, particularly preferably from 1 to 100, particularly preferably from 1 to 100, especially from 1.5 to 10. A production method characterized in that it has a span of particle size distribution d ₉₀ - d ₁₀ / d ₅₀ . The method according to any one of claims 1 to 5, wherein the silicon is metallic grade silicon and ultra-high purity silicon, wherein the proportion of metallic grade silicon is at least 50% by weight, preferably 70% by weight, based on the total weight of the contact material. % Or more, particularly preferably 90% by weight or more. 7. The method according to claim 6, wherein ultra-high purity silicon is a constituent of the fine particle fraction. The method according to any one of claims 1 to 5, characterized in that the silicon is metallic-grade silicon and ultra-high purity silicon, wherein the proportion of metallic-grade silicon is less than 50% by weight, and the granulation mixture further contains a catalyst. Manufacturing method to do. The process according to claim 8, characterized in that the ultra-high purity silicon and/or catalyst is a constituent of the fine particle fraction. Process according to any one of the preceding claims, characterized in that the silicon is ultra-high purity silicon and the granulation mixture contains a catalyst, and the catalyst is preferably a constituent of the fine particle fraction. The production method according to any one of claims 1 to 10, wherein the fine particle fraction and the coarse particle fraction are fed to the fluidized bed reactor as a granulation mixture prepared in advance. The production method according to any one of claims 1 to 11, wherein the fine particle fraction and the coarse particle fraction are each individually fed to the fluidized bed reactor. The method according to any one of claims 1 to 12, wherein the ratio of the height of the fluidized bed to the diameter of the reactor is from 10:1 to 1:1, preferably from 8:1 to 2:1, particularly preferably from 6:1 to The manufacturing method, characterized in that 3:1. The method according to any one of claims 1 to 13, characterized in that the chlorosilane is selected from the group comprising monochlorosilane, dichlorosilane, trichlorosilane, Si ₂ Cl ₆ , HSi ₂ Cl ₅ and mixtures thereof. Manufacturing method to do. 15. The method according to any of the preceding claims, characterized in that it is integrated into an integrated system for producing polycrystalline silicon.

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